Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

Spikings, Richard; Paul, André Navin; Vallejo, Cristian; Reyes, Pedro

doi:10.1016/j.gr.2020.10.009

Cited by 20 publications

(26 citation statements)

References 103 publications

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“…The time period between ~414 and ~294 Ma is mainly amagmatic in Ecuador, Colombia and Venezuela although geographically restricted and small granitoids in the northern Cordillera Central of Colombia yield Carboniferous zircon U-Pb dates [19], and were interpreted by Leal-Mejia et al 2019 [6] to have formed within an extensional environment focussed along the Otu-Pericos Fault (Figure 1). Spikings et al 2021 [1] suggest that northwestern Gondwana was mainly a passive margin during this period, which is reflected as a paucity of Devonian-aged zircons in Carboniferous basins in Ecuador. However, Horton et al 2010 [10] found a peak in Devonian-aged detrital zircons in Devonian sedimentary rocks in Colombia, leading them to conclude that a Devonian arc may have shed detritus into northwestern Gondwana, although the arc remains unidentified and it is possible that these zircons may be far travelled.…”

Section: Geological Framework and Previous Workmentioning

confidence: 97%

“…The oldest rocks are fault-bounded slivers of gabbroic to ultramafic rocks of the Huarguallá Gabbro unit within the Peltetec Fault Zone, located along the western flank of the Cordillera Real (Ecuador; Figure 1). These units yield imprecise 40 Ar/ 39 Ar dates (plagioclase) spanning between 623-531 Ma (including 2 s uncertainties; [1]), and the rocks are considered to have formed part of the Central Iapetus Magmatic Province during the rift stage of the Iapetus Wilson Cycle [1].…”

Section: Geological Framework and Previous Workmentioning

confidence: 99%

“…The first distinct group are two plateau 40 Ar/ 39 Ar dates (plagioclase) spanning between 582-566 Ma (623-531 Ma including 2 s uncertainties) from a gabbro and an ultramafic rock of the Huarguallá Gabbro, which are fault-bound slivers within the Peltetec Fault Zone of the western flank of the Cordillera Real in Ecuador (Figures 1 and 2) [1]. Neither zircon nor baddeleyite were found in these rocks and thus U-Pb dates were not obtained.…”

Section: Late Neoproterozoic: Continental Riftmentioning

confidence: 99%

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The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

Spikings

Lelij

2021

Geosciences

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Isotopic and geochemical data delineate passive margin, rift and active margin cycles in northwestern South America since ~623 Ma, spanning from the Iapetus Wilson Cycle. Ultramafic and mafic rocks record rifting associated with the formation of the Iapetus Ocean during 623–531 Ma, while the initiation of subduction of the Iapetus and Rheic oceans is recorded by continental arc plutons that formed during 499–414 Ma, with alternating compressive and extensional stages. Muscovite 40Ar/39Ar dates suggest there may have been a phase of Carboniferous metamorphism, although this remains tentative. A Passive margin was modified by active margin magmatism that started at ~294 Ma and culminated with collisional tectonics that signaled the final stages of the amalgamation of western Pangaea. Early Pangaea fragmentation included back-arc rifting during 245–216 Ma, leading to a Pacific active margin that spanned from 213–115 Ma. Trench retreat accelerated during 144–115 Ma, forming a highly attenuated continental margin prior to the collision of the Caribbean Large Igneous Province at ~75 Ma.

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Section: Geological Framework and Previous Workmentioning

confidence: 97%

Section: Geological Framework and Previous Workmentioning

confidence: 99%

Section: Late Neoproterozoic: Continental Riftmentioning

confidence: 99%

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The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

Spikings

Lelij

2021

Geosciences

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“…La Cordillera Real contiene rocas sedimentarias e ígneas metamorfoseadas del Paleozoico al Cretácico temprano, y quizás más antiguas (Spikings et al, 2021). Aspden y Litherland (1992) discriminan en divisiones tectono-estratigráficas las secuencias metamórficas de la Cordillera Real; de oeste a este, son: Guamote, Alao, Loja, Salado y Zamora.…”

Section: Cordillera Realunclassified

Evidencias de canibalización de secuencias Cretácicas y Paleógenas de la Cuenca Oriente en la cuña orogénica de los Andes ecuatorianos

et al. 2021

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Al sureste de la Cordillera Real, en la sección del río Miriumi, rocas sedimentarias e ígneas metamorfoseadas fueron agrupadas sin discriminación en la Unidad Upano, y la falla Palanda-Méndez-Cosanga fue considerada un límite de terreno en anteriores investigaciones. El objetivo de esta investigación es caracterizar y discriminar rocas sedimentarias e ígneas metamorfoseadas de la Unidad Upano, de rocas sedimentarias de la Cuenca Oriente. Esta discriminación está soportada en datos litoestratigráficos, identificación de estructuras sedimentarias, registro de fósiles, estudios petrográficos y análisis de datos estructurales. Rocas meta-volcánicas y meta-pelíticas afloran en la parte occidental de la sección; mientras que hacia el este de la sección, secuencias estratodecrecientes de conglomerados de cuarzo, cuarzo-areniscas, lodolitas y areniscas con estructuras mareales; calizas mudstone y wackstone, lutitas negras con abundantes trazas de amonites y bivalvos son afectadas por un pliegue anticlinal. En el río Upano, calizas y lutitas fosilíferas son cubiertas en discordancia por limolitas multicolores y red beds. Considerando la descripción inicial de la Unidad Upano, se restringe a esta secuencia a rocas meta-volcánicas y meta-pelíticas de bajo grado de metamorfismo en facies de sub-esquistos verdes relacionadas a la dinámica regional. En este estudio, cuarzo-areniscas y lodolitas con estructuras mareales son incluidas en la Formación Hollín, calizas y lutitas con Inoceramus sp. y Harleites sp. (?) son asociadas a la Formación Napo; y secuencias de red beds son vinculadas a la Formación Tena. La presencia de bloques y escamas tectónicas compuestos por las formaciones Hollín, Napo y Tena de la Cuenca Oriente en el frente de la cuña orogénica, afectadas por zonas de corrimiento y pliegues de arrastre indican que la falla Palanda-Méndez-Cosanga, no constituye un límite de terreno entre secuencias metamórficas de la Cordillera Real y secuencias sedimentarias de la Cuenca Oriente. Al contrario, nuestros datos concuerdan con el modelo de canibalización de secuencias de foreland.

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“…This area experienced accretion of the oceanic terranes form Western Cordillera and Coast of Ecuador. The mineral and petrographic content of the underlying rocks in Ecuador were formed as a result of the tectonic evolution which evolved in a backarc during the Ordovician and Carboniferous periods (Spikings et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Cartographic scripts for seismic and geophysical mapping of Ecuador

Lemenkova

2022

Geografie

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This research describes a script-based method of Generic Mapping Tools (GMT) for mapping the seismicity, geophysics, geology and topography of Ecuador. The advances of GMT include the following points: (1) automation of workflow; (2) refined aesthetics of graphics; (3) speed console-based mapping; (4) multi-format data handling; (5) advanced syntax. An explanation of scripting with the examples of code snippets is provided. The results present six new maps of Ecuador. The distribution of geophysical phenomena and seismicity is compared to the terrain elevation, showing remarkable correlations with the topography and geoid. The data demonstrated low values in the depression of the Andes, the Gulf of Guayaquil, and the Peru-Chile Trench. The peaks in gravity are representative for the Andean topography. Local decreases in gravity correspond to the depressions in the coastal shelf and the Gulf of Guayaquil. The increase in seismicity is detected along the tectonically active areas. The GMT is appropriate to the geological risk assessment of Ecuador.

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Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

Cited by 20 publications

References 103 publications

The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

Evidencias de canibalización de secuencias Cretácicas y Paleógenas de la Cuenca Oriente en la cuña orogénica de los Andes ecuatorianos

Cartographic scripts for seismic and geophysical mapping of Ecuador

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